Abrading



L. fW. GODDU F eb. 28, 1933.`

ABRADING Filed NOV. 6, 1929 Loro M Goood 57 INVENTOR B y/@Mg W A TTORNEY VII/Il Patented Feb. 2s, 1933 .,-UN51TED STATES PATENT OFFICE Y LLOYD: W. GODDU, OF SOUTHBRIDGE, MASSACHUSETTS, ASSIGNOR TO AMERICAN OPTI- COMPANY, OF SOUTHBRIDGE, MASSACHUSETTS, Al VOLUNTARY ASSOCIATION or MASSACHUSETTS ABRADING Application led November 6, 1929. Serial No.` 405,150.

' This invention relates to improvements in abrading and has particular reference to an improved means of abrading ophthalmic lenses.V f t The principal object of the inventlon 1s to provide means for producing ophthalmic lenses free from-aberration, waves and other irregularities. i i

Another. object of this invention is to provide means in the abrading machine to reduce friction and resultant wear which causes irregularities in the lens surface.

Another object of this invention is to provide asimple break-up or eccentric motion for abrading machine in order that the lens will not travel continually in the same path.

vAnother object of the invention is to reduce'V the amount of spoiled work 'associated with abrading processes. 'Qther objects and advantages will become apparent fromA the following description taken ,in ,connection with the accompanying drawings and it will be apparent that many changes may be made in the details of c onstruction and arrangement of parts Without departing from the spirit of the invention as expressed in the accompanying claims. I v

therefore, do not wish to be limited .to the exact details shownand described as the preferred forms only have been shown by way of illustration.

Referring to the drawing:

Y Fig. `I is a diagrammatic view of the invention applied yto a hand-operated machine.

Fig. II is an enlarged sectional view of l the device.v

i Fig. III is a diagrammatic view of a modilfied form applied to an automatic abrading .machine. l V4o,

fication. Y f Fig. `VI is a fragmentary side view of the v'modi-fied form shown in Fig. IV.

VInmthe abrading of ophthalmic lenses it is very @important that friction and resultant Vwear be reduced to a minimum in order that only the .desired path of travel will befol- .lowed `by the lens and no wavy motion or chatter will be transmitted to thel lens suri face destroying the desirable smooth surface. In` the pas'txthis factor of friction has been more or less ignored and the abrading process has been a lengthy one in the endeavor to remove the irregularities in the lens surface caused thereby. In my invention I have employed means to eliminate the cause of most of the friction and thereby have eliminated the wavy surfaces,.abrasion lines and other draw backs found in lenses abraded in prior machines. Referring to the drawings wherein similar characters of reference de note corresponding parts throughout the several views I have shown in Fig. I-the invention applied to the usual type of hand-sur facing machine. This comprises the -handle 1 pivoted for universal movement by the oint 2 which is supported by the arm 3 attached to an abrasive bowl 4. yCentrally arrangedgl in the bowl 4 is a support 5, carrying alap 6 of the desired curvature driven from a suitable source of power (not shown). The lens 7 to be abraded is attached to the usual block 8 by suitableadhesive means. The block 8 driving means. The foregoing construction is the usual one for the hand surfacing of ophthalmic lenses and the yparts havebeen shown in broken lines `in the drawings. The improved means provided by my invention relates specifically to the driving means for the lens block 8 and in a novel manner eliminates the undesirable frictionusually associated with this portion of the abradingv machine. y i

The improved driving means Vis Iattached to the handle 1 above the lap 6 and comprises a housing9 with hollow bosses 10 lying substantially normal .to the axis of the housing 9 and carrying the two ends of the handle 1 13. A ball bearing 15 is presse'llnto the has a `ball-seat 69 for the reception of the bore 12 and contacts with the seating 13. A second bearing 16 is fitted at the lower end of the bore 12 which has a recess 17 to receive it. The journal portion of the first bearing 15 is formed slightly smaller than the journal portion of the second bearing 16 in order that thereduced end 18 of the spindle 19 may fit therein with a shoulder portion resting against the bearing. The thrust from the abrading process will therefore be counteracted by the shoulder portion` coacting' with the bearing journal.

A cap 20 serves to retain the lower bearing 16 in the recess 17 and prevents oil orgrease from eXuding on to the lap 6 and the entrance of foreign matter. A pair of-felt pads 21 or other non-attrition means may be employed in the'bore 22 of the cap 20 which is made j slightly larger than the spindle 19 for clearance purposes.

Driving means for the lens block 8 may Yconsist of a peg 2-3 closely fitting into a suitable bore 24 inthe spindle 19 and may be held therein by the set-screw 25 fitting in the slot 26 in the peg 23. The height of the peg 23 may, of course, also be adjusted by the slot and screw means.

The end of the peg 23 is formed with a ball point 27 which lits into the ball seat 69 lof abrasion lines and no chattering or other irregularities will appear to destroy a smooth surface owing to the close-fitting yet freeacting ball bearing drive far removed from the loose and shaky mechanism heretofore employed at this part of the abrading device.

The operation of the device described is of a simple nature and consists of placing the lens block 8 and lens 7 in position on the lap 6. The ball pin 27 is then placed in seat 59 in the lens block 8 and the handle 1 used to hold it in position. The machine may then be set in motion and the lapwill rotate. The lens block 8 will also rotate from the friction between it and the lap 6 andthe block 8 may be moved in the usual way over the lap 6 to break up the abrasion lines'. A suitable abrasive may be employed during this opera tion. f f

It will be apparent that the spindle 18 will rotate with the lens block 8 and that the ball bearings 15 and 16 will serve to reduce the friction and resultant wear in the moving parts.

Having described the invention applied to a hand surfacing machine I can equally as ports 37 and driving'belt 38 running on pulley 39.

The lower end of the driving Shaft 3 6 iS b ored to receive the shank 40 of the cap 41 which is threaded on its periphery 44. A housing 42 has the upper portion Iof its .bore threaded to engage the threaded portion 44 of the cap 4. The smooth portion 43 Aof housing bore is adapted to closely fit a holding member 45 having an eccentric bore ther-ef 'in with recesses 46 concentric with the eccentric bore and tightly engaging ball bearings 47. The lower bearing 47 and lower face of the holding member abut a dust cap 51 which in turn abuts a flange 48 on the housing 42.

and dust cap 51 wil be pressed against 'the 'flange 48 on the housing. The flange 48 is bored to permit the eccentric spindle 49 to be moved around therein, as will presently be apparent. Y

The dust cap 51 curves downwardly at its center into pockets 52 formed for the purpose inthe spindle 49. It will be apparent that by this construction no dust can enter the beariings 47 and that the whole interior of 'the housing 42 may be filled with grease or other lubricating means without fear of it falling onto the lap 30 or work. l

The eccentricity of the spindle 49 may be adjusted to a definite amount by means 'of the trigger'member 62 which isattached to the holding member 45 and dust plate 51. By moving the trigger 62 the member 45 and plate 51 will move in the housing carry-l ing the spindle 49 with them whereby lit will'4 marked around the outside of the housing 42 s.

and a pointer 64 on the trigger member 62 indicatesthe amount of eccentricity. It wlll be apparent that in this way a deiinite amount of eccentricity may be set each time a certain curvature of lens is being abraded; that is, it may be found that a six diopter lens is best obtained by setting the pointer to number 6 on the scale and in this Way six diopter curves 'can be abraded at any time with this setting without further delay than positioning the pointer 64 to the same numiso ber 6. The spindle 49 may also be set perfectly concentric with the shank 40 at one position on the scale which may be number O. The setting may easily be accomplished by grasping the knurled portion and slightly loosening the housing 42 on the threaded cap 41 whereupon the pointer 64 may be rotated around the scale 68. rIhe housing 42 is then tightened onto the cap 41 which serves to press the cap onto the bearings46 and so lock the eccentric holding member 45 tightly in the position set.

It will be seen from the foregoing description that an eccentric motion has been imparted to the driving pin 54 around the'lap 30 by means of the offset spindle 49. This motion is necessarily formed by offsetting said spindle to duplicate, as far as possible1 the motion which may be applied without such offsets in the hand-operated machine previously described. In this manner the travel of the lens is never twice in exactly the same path on the abrading tool and no abrasion lines will be formed. To this feature I have added the absence of friction and resultant wear causing aberration and wavy surfaces by means of the smoothly running ball bearing in the manner described.

To provide a differential motion also in this device I have illustrated in Fig. V an eccentric spindle 57 which produces in the ball pin 54 an off-center effect by having the center line 58 of the pin oset from the centerline 59 of the spindle 57 at its point of juncture with'the bearing 47. A break-up motion will be imparted to the lens in the lap and greatly assist in the production of improved lens surfaces.

The operation of these power driven devices is similar to the manually operated'one inasmuch as in Fig. IV the ball pin 54 is seated in the lens holder 35 carrying the lens and is rotated therewith. The outer ring of the bearing will be engaged with the eccentric plate which is rotated by separate power means. The pin 54 will be given a rotating movement on its axis and an eccentric rotation round the lap as will be clear.

In Fig. V the pin 54 is also eccentric to the axis of its bearing 47 and so will have a further eccentric or break-up motion over the lap 30.

From the foregoing it will be apparent that I have provided means to apply a drive to lens surfacing machines which will greatly reduce the friction hitherto unavoidable, allow the block to spin freely over the lap and reduce the wear between the ball pin and lens holder socket which produces the irregularities such as waves and aberration.

Having described my invention, I claim:

1. In a device of the character described a detachable support having an eccentric portion, a housing attached to said eccentric portion, said housing having a rotatable bearing support therein, said bearing support being rotatable about an axis offset from and extending substantially parallel with the longitudinal axis of the detachable support, a bearing in the bearing support offset from the axis of said bearing support and a rotatable pin member in said bearing, said pin member being adjustable to varying positions relative to the axis of the detachable support.

2. Ina device of the character described, a detachable support having an eccentric portion, a housing attached to said eccentric portion, said housing having a rotatable bearingl support therein, said bearing support being rotatable about an axis oset from and extending substantially parallel with the longitudinal axis of the detachable support, a

bearing in the bearing support oset from the axis of said bearing support, and a rotatable pin member in said bearing, said pin member being adjustable to varying positions relative to the axis of the detachable support, the connection of the housing to the detachable support providing means whereby the said housing can be adjusted to clamp the rotatable bearing support against movement when the pin member is in desired adjusted position.

LLOYD W. GODDU. 

